The present invention is directed to a power plant and, more particularly, to an interface member for a power plant.
Steam turbines particularly combined cycle plant (CCP) steam turbines include an Intermediate Pressure (IP) turbine and a Low Pressure (LP) turbine that are joined by a vertical joint. A substantial portion of fluid flow at or near the vertical joint is exhaust flow from the IP turbine. One or more nozzles supply LP steam that is combined with a high temperature leak-off steam from another portion of the power plant through radial pipes near the vertical joint. When there is little or no supply of LP steam, the high temperature leak-off steam dominates the flow through the nozzles. The combination of IP exhaust and high temperature leak off steam creates a non-uniform circumferential temperature distribution at the vertical joint, in shell members, and also around first stage nozzles of the LP turbine. Large circumferential temperature variations may result in distortions at the vertical joint. Distortions at the vertical joint eventually lead to steam leakage, which lowers turbine efficiency. High peak temperatures in at the vertical joint will also negatively affect material strength properties of carbon steel plates used to form a LP hood section of the LP turbine.